calculating size of column with specified value in the column

For calculating the values of e1 == 1, the code is

D1 = e1(e1(:,2)==1);

r1 = size(D1);

DDDx = r1(1,:);

I want to calculate the values for comparing 50 values

For example

D2 = e1(e1(:,2)==2);

r2 = size(D2);

DDDx2 = r2(1,:);

D3 = e1(e1(:,2)==3);

r3 = size(D3);

DDDx3 = r3(1,:);

.

.

.

D50 = e1(e1(:,2)==50);

r50 = size(D50);

DDDx50 = r50(1,:);

Answer 1

[Torsten]

DDDx = zeros(50,1);
for i = 1:50
  DDDx(i) = numel(e1(e1(:,2)==i));
end